Mitotic cell division

Cell division

1. Mitotic cell division RINI JOSEPH

2. Definition Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells . During cell division , mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus .

3. Phases of mitosis Mitosis consists of four basic phases : Prophase Metaphase Anaphase Telophase

4. EARLY PROPHASE : In early prophase , the cell starts to break down some structures and built others up setting the stage for division of the chromosomes . » The chromosomes start to condense. » Mitotic spindle begin to from – microtubules , strong fibers that are part of the cells “skeletal ”. » The nucleolus a part of the nucleus where ribosomes are ,made disappears .

5. Prophase : The chromosomes condense and become visible - chromatids . The centrioles form and move toward opposite ends of the cell(“the poles”) The nuclear membrane dissolves The mitotic spindle forms . Spindle fibers from each centriole attach to each sister chromatid at the kinetochore.

6. Creating kinetochores Microtubules attach at kinetochores Connect centromeres to centrioles Chromosomes begins moving.

7. Metaphase: Chromosomes align along middle of cell Metaphase plate Meta=middle Spindle fibers coordinate movement Helps to ensures chromosomes separate properly So each new nucleus receives only one copy of each chromosome

8. Anaphase Sister chromatids separate at kinetochores Move to opposite poles Pulled at centromeres Pulled by motor proteins “waking” along microtubules Increased production of ATP by mitochondria Poles move farther apart Polar microtubules lengthen

9. Separation of chromatids In anaphase, proteins holding together sister chromatids are inactivated. Separate to become individual chromosomes. Chromosome movement Kinetochores use motor proteins that “walk” chromosome along attached microtubules. Microtubules shortens by dismanting at kinetochore(chromosome ) end.

10. Telophase Chromosomes arrive at opposite poles Daughter nuclei form Nucleoli form Chromosome disperse No longer visible under light microscope Spindle fibers disperse Cytokinesis begins Cell division

11. Cytokinesis Cytokinesis is often mistakenly thought to be the final part of telophase. Cytokinesis is a separate process that beings at the same time as telophase. Cytokinesis is technically not even a phase of mitosis , but rather a separate process Necessary for completing cell division . In animal cells, a cleavage furrow (pinch) containing a contractile ring develops where the metaphase plate used to be pinching off the separated nuclei.

12. In both animal and plants cells, cell division is also driven by vesicles derived from the golgi apparatus, which move along microtubules to the middle of the cell In plant cell this structure coalesces into a cell plate at the centre of phargmoplast and develops into a cell wall, separating the two nuclei.

13. Thank you